miniSASS Newsletter July 2015

miniSASS Newsletter July 2015

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nunu of the month: True fly

Strip

Phylum: Arthropoda
Class: Insecta
Order: Diptera

Some true flies can tolerate really filthy oxygen depleted water and use haemoglobin (red blood worm) or “snorkels” (rat tailed) to survive in these conditions.


The true flies are a very large and very diverse group. The Diptera is one of the largest orders with most of their families having an aquatic based larval stage. Their common physical traits are their elongated worm-like bodies, eyes and pro-legs. Their bodies can also be soft and naked; others have structural adaptations like being able to stick to solid surfaces (mosquitoes and black flies).

The true flies eat dead organic matter, and some breathe through their skin, others aren’t able to get the oxygen and have special structures to get atmospheric oxygen in the air. Mosquitoes and rat tailed maggots actually have “snorkels” that are pushed through the surface film to get the oxygen. True flies are found dwelling at the bottom, adhered to different substrates or free swimming; they can swim with strong and fast wriggling motions while others crawl using suckers, spines or pro-legs to drag themselves around.

The true flies have been thought of in a bad way because they are able to survive really poor conditions and multiply rapidly in those conditions. True flies are also sometimes the hosts of deadly diseases like malaria. However, this group serve a great ecological function of decomposing dead matter and they use up the “filth” to clean the system. They score a low 2 in the miniSASS because they are not sensitive to pollution, except for the net winged midge that is found only in the clean waters of mountain streams.

True flies undergo complete metamorphosis, passing through four life stages. The eggs are deposited in shallow fast-running water, either attached to a substrate or scattered on the surface of the water. After hatching the larvae are released, this is also an aquatic phase. The pupa form and this phase does not last long, depending on the temperature of the water and the conditions. The pupa are in a case or a hardened skin, pupa also count in the miniSASS. The case splits and the young adult emerges.

Nunu Of The Month: The Other Mayflies

Other Mayflies

Phylum: Arthropoda

Class: Insecta

Order: Ephemeroptera

Mayfly larvae are the “cows” of freshwater streams and graze on algae. They swim by moving their abdomen up and down. The adult mayfly doesn’t eat at all and lives only for a few hours or days.

The other mayflies are a large group and they vary significantly. The common physical traits include three elongated tails, an elongated body, a large head, well developed mouth parts and true legs. Other mayflies have their gills on their abdomen, there is variation between the shape and the location of the gills.

The other mayflies are the cainflies which have a skirt like covering of the gills, the flat-headed mayfly that has a head broader than their body, the prongills that have gills with a unique shape and the stout crawlers that have very thick and stout arms. Others also include the brushlegged mayflies, pale burrowers and the water specs.

Other mayflies are the cows of the rivers as they graze on the algae and plant matter that grows on the rocks and on the floor in-stream. They breathe using the gills and move by swimming and crawling. The other mayflies are part of the diet of small fish, trout, frogs and birds. With a score of 11 on the miniSASS, other mayflies are moderately sensitive to pollution.

Mayflies undergo incomplete metamorphosis as they do not have a pupal stage. This involves passing through 3 life stages which are egg, nymph and adult. Each of these stages requires that the mayfly remain close to the water, the nymph is entirely aquatic whilst the adult is not aquatic but always stays close to the water.

Citizens indispensable in modern biodiversity protection

The article as it appears on The Water Wheel on the May/June 2014 volume 13 No 3 issue.

Get the whole publication online: www.wrc.org.za

WaterWheel_2014_3_May-page-010WaterWheel_2014_3_May-page-011

WaterWheel_2014_3_May-page-012

WaterWheel_2014_3_May-page-013

 

 

nunu of the month: Flat Worm

Aquatic Nunu’s are part of miniSASS and here we learn about their amazing facts and interesting adaptations.

This month we look at: The Flatworm

Strip

Interesting fact:

Planaria have their mouth at their stomach, breathe through their skin and can reproduce asexually by simply splitting in two or become two separate animals if cut in half

Scientific Classification

Phylum: Platyheminthes

Order: Tricladida

Genus: Planaria

Freshwater flatworms are dorsoventrally flattened with an arrow shaped head. There are very distinguishable eyespots on the head and have a white belly. Flatworms breathe through their skin and cannot swim, instead they smoothly glide over solid substrates. Flatworms are sensitive to strong light and prefer shaded areas and under rocks.

Flatworms are relatively tolerant of pollution with water quality scores ranging from  3-4. Some flatworms are carnivorous and other can be scavengers. They eat bacteria, protozoans and other animal matter that may be available.

Flatworms are hermaphroditic (having both male and female sex organs) and they reproduce both sexually and asexually. Asexual reproduction occurs under environmentally stressful conditions.

Nunu of the month: True Bug

miniSASS uses various aquatic macroinvertebrates to tell the river health and general water quality of the river water. One group that is considered is the true bug.true bugs

Interesting fact:
All bugs have piercing mouthparts. Some use these mouth parts to pierce and suck the juices out of their prey. The Nepidae use their tails as a snorkel whilst the Gerridae, Veliidae and Hydrometridae can actually walk on water!

Scientific Classification:

Kingdom: Animalia

Phylum: Arthropoda

Order: Hemiptera

Sub-order: Heteroptera
Families: Gerridae (Pond Skaters/Water Striders), Naucoridae (Creeping Water Bugs), Belastomatidae (Giant Water Bug), Corixidae (Water Boatman), Veliidae (Ripple Bugs), Hydrometridae (Water treaders), Pleidae (Pygmy Backswimmers), Notonectidae (Backswimmers), Nepidae (Water Scorpions)

Some families are predators and are carnivorous and other families eat plants in the water. Each family is structurally suited for life in the water, Veliidae, Gerridae and Hydrometridae are able to run and float on the surface whilst families like Corixidae and Notonectidae have powerful legs for swimming. Respiratory mechanisms differ between those that stay on top of the water, which would be similar to those of terrestrial macroinvertebrates, and those of the families that live below the water, which may occasionally need to come up to access more air.

True Bugs are relatively tolerant of pollution with water quality scores ranging from  3-7.

True bugs undergo incomplete metamorphosis. The young bugs are called nymphs and they look like their adult form. They moult till they become adults. Their final transformation involves the development of wings and sexual organs.

miniSASS as part of mini-IHI

One thinks of what could be the adverse effects on the aquatic ecology of a river that has a wier, bridge, a piggery, waste water treatment works of a little town releasing water effluent into it. The water may look clean, and the plants may look green, we might even see the odd antelope and think that this river is doing okay. However that is far from the true reflection of the river health of the UMlaas River.miniSASS uMlaas River IHI

If we look at these attributes autonomously; a waste water treatment plant releases treated effluent into the river system. This effluent is a result of sewerage leachate that has been

treated physically (bulk removal), biologically (use of microorganisms to degrade or at least reduce the toxicity of a waste stream says G. le Roux) and finally chemically where processes like neutralisation, oxidation, precipitation and wet-air oxidation are performed. Once it meets the criteria and standards to discharge into natural water ecosystems

(DPW, June 2012) it is released into a river or groundwater system.

Abattoir waste is discharged (after appropriate pre-treatment) to municipal sewer. These

effluents have to comply with municipal by- laws which could be typically described as: COD £ 3000 to 5000 mg / L; TSS £ 500 mg / L; NH3-N £ 200 to 300 mg / L; pH 6 to 10 (DWA draft 2001). Are these standards enough to ensure no significant impact on the ecosystem?

The  team Mahommed Desai of GroundTruth and Sthembiso Sangweni of the Duzi Umngeni Conservation Trust.

The presence of a wier significantly alters the flow of the river. People driving on the bridge may throw wastes in to the river. Also, water abstraction directly impacts the habitat. On cannot just look at what is present but also must consider what is absent and ask why is it absent? Today, look in a river you know and ask yourself; is all that should be in that ecosystem present…

In aquatic ecology, we look at the riparian zone and the instream habitat integrity (IHI) of a river system in order to get a clear picture about the river health. Factors that are considered in the IHI include water abstraction, flow regulation, bed and channel modification, exotic vegetation, inundation, exotic macrophytes and aquatic fauna, solid waste disposal, bank erosion and water quality (Kleynhans CJ, 1996). We figured miniSASS could be incorporated as a measure of water quality. With gumboots and net in hand we went to the uMlaas river just to find out what is going on in that river. We took special note of the uMlaas River as the Duzi uMngeni Conservation Trust (DUCT) have Green teams that are working on the river, clearing alien plants.

So Mahommed, Sthembiso Sangweni (DUCT) and I went for it. Gumboots… check! Let’s go!

We arrive in the UMlaas River in the morning and we find a good flowing Rocky River with riffles, there has been vegetation clearing by fire around the river. The water looks clear and you can see the green algae on the rocks, the bedrock has accumulated sand and silt. This site had a miniSASS score of 5.8 which places the river at a poor river category. There was also foaming around some rocks. Could this be because of the upstream bridge, the burning of vegetation or the wier? The clarity of the river was 93cm which is outstanding, indicating little total dissolved solids. This is the first miniSASS of this river story…

The effluent from the piggery is being discharged directly into the river and the vegetation instream vegetation ceased thereafter. Mahommed sighted the remains of a crab and footprints of a Mongoose. How fun, we saw these later in a tree. The foaming was getting thick, although it could have occur naturally by the interactions between the water adhesion forces and the leaves and the air causing tiny bubbles but it may have been due to chemical products in the water.

We continued walking in the sun; we entered the forest following a little path used by bucks to get to the water. To find that this river ecosystem is severely damaged with a miniSASS putting it in the poor ecological category, severe case of invasive plant species namely Rebus cuneifolius, commonly known as American bramble, Opuntia stricta, common name prickly pear and Acacia mearnsii the Black wattle. There were numerous thorns and I have the cuts and scratches to prove it.

The second miniSASS, gave a “fair” score of 6.25 and a clarity reading of 90cm. We had a few reed buck and daicker sightings and droppings along the way. We noticed the river to be turning milky green in colour, although we could not get to it. The waste water treatment plant soon followed and it contributed to this ecosystem. It brought peace in our hearts to know that DUCT’s green teams will soon be coming to clear the invasive.

For a moment we stood there in awe at the invasive vegetation, thinking about how adversely it is affecting the river. Invasive plants take up a lot of the ground water and alter the natural habitat, also overtaking the indigenous species by challenging them for space, light, food, water and nesting places. In this case, the alien plants intensify flooding zones, soil erosion and destroying the river. We could hear the river flow but could not get to it (wessa.org.za). How sad.

Anelile, SANBI Groen Sebenza intern tries to get minisass sample.

Anelile, SANBI Groen Sebenza intern tries to get minisass sample.

Our walk had to end on an unfavourable part as we were about to go any further as it was privately owned property, unfortunately we had no means to go further. We tried to get miniSASS upstream of the bridge reading but failed due to the river depth… I tried and nearly died! I think I need wings or a bigger net next time. All in a day’s work.

References

  1. Department of Water Affairs. Guidelines for the handling treatment and disposal of abattoir waste. Draft 1 – 29 august 2001.
  2. Kleynhans CJ. 1996. A qualitative procedure for assessment of the habitat integrity status of the Luvuvhu River (Limpopo system, South Africa).Journal of Aquatic Ecosystem Health 5: 41 – 54.
  3. Department of Water Affairs. Guidelines for leachate control. Compiled by G. le Roux
  4. Department of Public Works. Small waste water treatment works dew design guidelines. PW 2011/1
  5. wessa.org.za
. minisass

miniSASS is a comminity river health monitoring tool

Aquatic Insects of Central Virginia

miniSASS is a comminity river health monitoring tool

River Walks

Journeys from the Source to the Sea